Hiram s



I H. S. MAXIM. Oommutator for Magneto-Electrical Machines.

Patented June 8,1880.

INVENTOR WITNESSES J/ ".PETERS FHOTO-UTHOQIAPHER. WASHINGTON. D C.

UNITED STATES PATENT OFFICE,

HIRAM S. MAXIM, OF BROOKLYN, ASSIGNOR TO SPENCER D. SOHUYLER, OF

NEXV YORK, N. Y.

COMMUTATOR FOR MAGNETO-ELECTRICAL MACHINES.

SPECIFICATION forming part of Letters Patent No. 228,545, dated June 8, 1880.

Application filed October 22, 1879.

To all whom it may concern:

Be it known that 1, HIRAM S. MAXIM, of the city of Brooklyn, county of Kings, and State of New York, have invented a new and use- Fill Improvementin Uommutators for Dynamo lYIagnetoElectrio Machines, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part hereof.

- Such comniuta-tors are commonly made in cylindrical form, and are composed of a series of plates or strips of conducting material corresponding in number to the divisions or coils of thearmature, and separated from each other by insulating material; but the conductingstrips have heretofore been arran god i n straight lines parallel to the axis of the cylinder or in a spiral direction, and both thesearrangements are subject to serious objections. Where the strips are straight and parallel to the axis the comm utator-brush often breaks contact with one strip before it c'oines into contact with the succeeding one, which not onlyinterrupts and weakens the current, but greatly increases the -2 wear of the commutator. When the plates are arranged in spiral form this objection is overcome; but the shrinkage of the insulating material between them allows thepiteh of the spiral to increase and shortens the cylinder, thus loosening the plates in their clamps. Moreover, the wear of the commutator takes place, for the most part, at the point where the spark passes between the commutator-strip and the brush, and as this must always take place at the same end where the plates are made spiraling in one direction, one end of the commutator so constructed wears much more rapidly than the other, which is objectionable.

I obviate these objections by making the commutator-plates of such form that they are parallel to the axis of the cylinder on the in side and take the direction of a double spiral on the outside. This arrangement secures all 4 5 the advantages of the spiral arrangement, and at the same time prevents the plates from working loose and secures an even wear for the two ends of the commutator.

In the drawings, Figure 1 is a central lengitudinal section of a commutator constructed according to my invention. Fig. 2 is a side elevation of the same. Fig. 3 is a transverse section, and Fig. i is an end elevation. Figs.

5 and 6 are views of commutator-plates constructed in accordance with my invention, (but 5 5 of somewhat differentpatter-11s,) lookin g from the direction of the thinner or inside edge. Figs. 7 and 10 are side views of the same, and Figs. 8 and 9 end views.

The double spiral arrangementof the plates at the surface of the cylinder is best shown in Fig. 2.

A A are the comm u tatorplates, and B B are the divisions of insulating material between them. 0 G are the projecting arms of the plates, to which the sections or coils of the armature are connected.

As will be seen in Figs. 3, 8, and 9, the commutator-plates are made thickest upon the outside edge, and form sectors of the commutator- 7o cylinder.

In an application for Letters Patent for an improvement in dynamoinagneto-electric niachines filed by me February 25, 1871), I have shown radiating bars upon the commutator, in combination with bars of metal upon the periphery of the hub and an insulatin washer and nut; and 1 do not wish to include or claim such combination in the present application; but,

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. A commutator in a dynamomagneto-electric machine having its conducting-plates so 85 constructed and arranged as to form a double spiral upon the outside, and to be parallel to the axis of the commutator upon the inside, substantially as described, and for the purposes set forth.

2. A commutator for a dynamo-inagneto electric machine having its conducting-plates arranged in the form of a double spiral, substantially as described, and for the purposes set forth.

HIRAM S. MAXIM.

Witnesses Units. 0. ULAGGETT, LEONARD E. Gon'ris. 

